Changes in Some Enzymes Activities of Amaranthus viridis L. Inoculated with Telfairia Mosaic Virus (TeMV)

Abstract

Introduction: Investigations were carried out to assess changes in some enzymes activities of Amaranthus viridis (A. viridis) inoculated with Telfairia mosaic virus (TeMV). Methodology: Symptoms of Telfairia mosaic virus (TeMV) are characterized by severe mosaic and leaf malformation. Healthy and inoculated leaves of A. viridis were assayed for changes in peroxidase (POD), polyphenol oxidase (PPO), glucose-6-phosphate dehydrogenase (G6PdH) and 6-phosphogluconate dehydrogenase (6PGdH) activities spectrophotometrically at wavelengths appropriate for each enzyme for a period of 120 days after inoculation (DAI). Activities of enzymes in TeMV inoculated and healthy plants of A. viridis were measured in µg-1 FW and U/L. Results: Results revealed a gradual increase in activities of POD and PPO from 14 - 60 DAI, followed by a decline at 90 DAI and a subsequent increase at 120 DAI in inoculated plants while G6PdH and 6PGdH activities showed gradual increase from 14 – 30 DAI, followed by a decrease from 60 – 90 DAI and subsequent increase at 120 DAI. Activities of POD, PPO, G6PdH and 6PGdH at all periods of growth were significantly (P = 0.05) higher in inoculated plants compared to the healthy. Results also revealed that activities of all enzymes in U/L were significantly higher than activities in µg-1 FW. Fluctuation in all assayed enzymes activities was observed in inoculated samples. Highest percentage increases in enzymes activities in µg-1FW for POD, PPO, G6PdH and 6PGdH were 54.3%, 45.3%, 55.3% and 44.6% respectively. Corresponding activities in U/L were 81.2%, 86.2%, 91.3% and 87.0%. Conclusion: Activities of all enzymes were found to increase in inoculated leaves due to TeMV infection when compared to healthy leaves. Changes induced by TeMV infection led to increase and fluctuation in all enzymes activities with alterations in physiological processes of A. viridis climaxing to poor growth and reduction in yield.